1. Field of the Invention
This invention relates to cleansing preparations, especially hand cleansers, which self-decontaminate through the inclusion of hydrogen peroxide, but which nevertheless retain desired viscosities through the further inclusion of fatty acid alkanolamides and water-soluble alkali and/or ammonium salts.
2. Statement of Related Art
Water-miscible concentrates having a high surfactant content, for example of the handwashing lotion type, are ideal nutrient media for microorganisms, so that these products have to be protected against attack and decomposition by microorganisms, particularly bacteria, fungi and spore formers. The undesirable introduction of microorganisms such as these can occur, for example, during the preparation or during the use of the products. It is standard practice to protect cleansing preparations (or rather corresponding concentrates of the type in question) by means of preservatives, of which only a limited number are permitted under cosmetics legislation in many countries.
In most places, handwashing lotions are not subject to legislation or medicaments, although they have to satisfy praticular requirements in practice, particularly in the medical field, i.e. in hospitals, in general practice or, generally, in patient care. In the particular applications in question here, the water-miscible lotions are in greater danger of contamination by pathogenic microorganisms and spore formers. Accordingly, the corresponding cleansing preparations have to be able to eliminate any contamination occuring on their own. This is not possible with conventional preservatives which, in the permitted in-use concentrations, show only microbistatic activity and no microbicidal activity.
In order, therefore, to develop autosterile cleansing preparations of the handwashing lotion type, for the medical field, possibilities must be sought for achieving microbicidal activity by addition of small quantities of toxicologically and, in particular, dermatologically safe compounds in addition to the stabilization already achieved by the addition of preservatives.
It is known that self-decontaminating skin disinfectants can be obtained by addition of small quantities of hydrogen peroxide to aqueous disinfectants. Thus, published German patent application No. 29 04 217 describes disinfectants based on aqueous alcohol solutions additionally containing small quantities of hydrogen peroxide. Disinfectants of this type are capable of destroying involuntarily introduced spores and, thus, of keeping the disinfectant germ-free in use.
In order to improve the heptics (tactile qualities) and the handling of cleansing preparations of the type described above and, more particularly, handwashing lotions, it is standard practice to adjust them by means of organic thickeners to viscosities in the range of from 500 to 5,000 mPas and, more particularly to viscosities of from about 500 to 4,000 mPas, as measured with a Brookfield LVF rotational viscosimeter at 20.degree. C., spindle 4/20 r.p.m. The addition of hydrogen peroxide to thickened surfactant-containing cleansing concentrates such as these seriously complicates their formulation, because the viscosity-regulating properties of conventional thickeners are lost by the addition of even small quantities of hydrogen peroxide.